Automatic threading device for rolling mills



P. M. LOWY 3,422,649

AUTOMATIC THREADING DEVICE FOR ROLLING MILLS Jan. 21, 1969 Sheet Filed Jan. 14, 1966 INVENTOR. Paul M. Lowy I?! g a %/?g P. M. LOWY 3,422,649

AUTOMATIC THREADING DEVICE FOR ROLLING MILLS Sheet 2 of 4 Filed Jan. 14, 1966 .y R W may N L 7 T M m u q u 0% P M/ Y/M B P. M. LOWY 3,422,649

AUTOMATIC THREADING DEVICE FOR ROLLING MILLS Jan. 21, 1969 Sheet Filed Jan. 14, 1966 INVENTOR. Paul M. Lowy Jan. 21, 1969 P. M. LOWY 3,422,649

AUTOMATIC THREADING DEVICE FOR ROLLING MILLS Filed Jan. 14, 1966 Sheet 4- of 4 INVENTOR. Paul M. Lowy 5& X

United States Patent 3,422,649 AUTOMATIC THREADING DEVICE FOR ROLLING MILLS Paul M. Lowy, Pittsburgh, Pa., assiguor to Mesta Machine Company, Pittsburgh, Pa., a corporation of Pennsylvania 14, 1966, Ser. No. 520,573

Filed Jan.

0 13 Claims Int. Cl. B21b 37/02; B21c 51/00 US. Cl. 72-1 ABSTRACT OF THE DISCLOSURE and means for moving the belt laterally of the strip path.

My present invention relates to rolling strip mills and more particularly to the automatic threading and centering of a moving strip traveling through the mill.

A serious problem involved in the operation of cold strip mills and the like has been the difficulty of threading the strip through the one or more mill stands prior to commencement of the rolling operation. Of course, with each increase in the number of stands or rolling stations of the mill, these difficulties are, of course, correspondingly multiplied. The strip must be guided into alignment with the center line of the mill rolls at each stand in order to impart uniformity of cross-section to the strip. Because of the thinness of the strip and its attendant tendency to crease or tear, the strip is exceedingly difficult to manipulate and is readily subject to damage from improper threading or from other mishandling. When threading strip material to the several stands of a multiple mill, the head end or leading edge of the strip must be threaded through the several stands without causing buckling or other damage to the strip. This must be accomplished by providing some means for guiding the leading edge of the strip along the center line or longitudinal axis of the mill without deviation of the center line of the strip from that of the mill.

As the strip is threaded from the uncoiler or the payout coil to the first stand of the mill, and between stands the head end of the strip is loose, i.e., without tension since it is urged from behind during the threading operation. For this reason, the strip is difficult to guide and has a tendency to cobble or buckle, until the threading operation is complete and the strip is tensioned and Wound upon the coiler or tension reel. Because of the flexibility of the strip, and owing to its being urged from behind, it is likely that the strip will be off center in the mill rolls with the result that unequaled thickness is imparted and also that the skewing or camber occurs in the strip edges.

For the foregoing reasons, attendants have usually been employed in connection with the operation of the mill for manually guiding the head end of the strip through the stands. Because of the coat in time and wages of this practice, efforts have been directed toward automatic threading and centering of the strip in the rolling mill.

Prior attempts to solve these problems involved the use of an apparatus including a movable clamp which is actuated to grip the head end of the strip and to urge it forward in its path through the rolling mill. This procedure is repeated at successive stands until the mill is completely threaded. The equipment provided to perform these operations is not only bulky and expensive, but requires considerable maintenance.

3,422,649 Patented Jan. 21, 1969 Prior attempts to center a strip in a given mill stand involved the use of the normally provided screw-down drive of the previous stand. By applying unequal screwdown forces to the work rolls adajcent the corresponding edges of the strip, the resultant imbalance in frictional forces caused the strip to be urged to the right or to the left of the center line of the rolling mill, which is determined by the predominating screw-down force. Although this centering method does not require any additional equipment, it is unsatisfactory in that attendants must be still employed for its operation. Moreover, the directing forces are applied to the strip at a distance con siderably removed from the head end which it is desired to steer. The length of the intervening strip section, however, makes the control of the head end sluggish and uncertain.

These problems are solved by my apparatus which includes means for urging the free or head end strip through the mill by engaging the strip at or immediately adjacent the head end. Thus, it is not necessary to urge the strip through the mill by urging it from considerable distance behind the head end. My apparatus also includes means sensitive respectively to the location of the lateral edges of the strip to ascertain whether the center line of the strip is displaced from the center line of the mill. Such means are further arranged automatically to actuate a steering control for the head end of the strip, which steering control is moved to the right or to the left of the mill center line in order to compensate for opposite displacement of the strip as it is threaded through the mill.

In accordance with another arrangement of my apparatus, means are provided for greatly increasing the flexibility of the strip about a vertical axis so that the aforementioned steering corrections can be readily made. This is accomplished by non-deformably distorting the normal path of the strip so that portion of the strip requiring steering, which is, of course, disposed adjacent to the distorted path, can be revolved or displaced angularly about a vertical axis for steering purposes.

In a rolling mill constructed in accordance with my invention, each stand of the tandem strip mill can be equipped as described above and the operation is essentially the same for each stand. The stands preferably are threaded successively at a common speed, and at the completion of threading of a particular stand, that stand is placed under proper tension control.

These and other objects, features and advantages of the invention together with structural details thereof, will be elaborated upon during the forthcoming description of certain presently preferred embodiments of the invention and certain presently preferred methods of practicing the same.

In the accompanying drawings, I have illustrated certain presently preferred embodiments of the invention and have shown a presently preferred method of practicing the same, wherein:

FIGURE 1 is a side elevational view, partially in section and partially broken away, of one form of strip rolling mill arranged in accordance with my invention;

FIGURE 2 is an enlarged side elevational view of one of the feeding and centering apparatus incorporated with the rolling mill of FIGURE 1;

FIGURE 3 is a top plan view, partially sectioned of the apparatus shown in FIGURE 2;

FIGURE 4 is a side elevational view of another form of the feeding and centering apparatus of my invention;

FIGURE 5 is a top plan view of the apparatus shown in FIGURE 4;

FIGURE 6 is a schematic circuit arrangement associated with the apparatus of FIGURES 4 and 5 for 3 automatically energizing the steering mechanism thereof; and

FIGURE 7 is a block circuit diagram of one arrangement for operating means associated with the apparatus of FIGURES 4 and 5 for increasing the flexibility of the strip about a vertical axis.

Referring now more particularly to FIGURES 1-3 of the drawings, a rolling mill arranged in accordance with my invention includes a plurality of roll stands A, B, and C which in this arrangement are of substantially identical construction. It will be understood, of course, that a greater or less number of stands can be employed depending upon the application of the rolling mill. At the entrance station of the rolling mill the head end of the strip is taken from the pay-out or uncoiling reel and is conducted through an entry tension device denoted generally by reference character 12 of known construction. The strip is then passed successively over and under deflectable tensioning rolls 14 and 16 respectively between which is disposed tensionmeter roll 18, and over an adjustably elevatable pass defining roll 20, the elevation of which is controlled by hydraulic cylinder 22. The roll 20 pre-disposes the strip at the proper elevation thereof for passage between work rolls 24 of the first stand A. In accordance with conventional procedures the work rolls 24 are compressed against the upper and lower surfaces respectively of the strip by means of back-up rolls 26. The apparatus as described thus far is conventional in nature, and therefore, has not been elaborated upon in great detail.

At the entrance to the other stands B and C, similar tensioning rolls 14 and 16, tensionmeter roll 18, and elevational roll 20 are disposed for the purposes identified above. Additionally, a wringer roll 28 is associated with one of the tensioning rolls, for example the roll 14, to position the strip within an adjacent X-ray gauge 30. An exit X-ray gauge .30 also is disposed at exit deflecting rolls 32 from which the strip is passed to a tensioning or coiling reel 34.

In the exit path from the last stand C, the strip is deflected in accord with known procedures by a series of deflector rolls 36, 38, and 42, and for this purpose the first-mentioned deflector roll 36 is mounted adjacent the rearward end of deflector table 44 the forward end of which is pivoted about the deflector roll 38, and the table is displaceable angularly about the aforementioned pivoted mounting by means of the piston arrangement 46.

Disposed at the entry side of stand A or intermediately of the stands A and B, and B and C is a strip threading and centering table denoted generally by the reference character 48. Each table 48, which can take the form of that detailed in FIGURE 2 or of the alternate form 48' illustrated in FIGURE 4, is mounted upon a platform 50 and as shown in FIGURES 13 of the drawings, the table 48 includes a lower generally planar stand 52 upon which are mounted a pair of spaced rolls 54, 56 and a pair of belt-tensioning rolls 58, 60. A continuous conveyor belt 62 passes over the rolls 54-60 as better shown in FIG- URES 2 and 3 of the drawings. The elevation of the strip as it leaves the forward roll 56 can be adjusted by means of elevating piston and cylinder arrangement 64.

In furtherance of this purpose, the for-ward roll 56 is rotatably mounted upon a hinged front end portion 68 of the table 48, which portion is pivoted or hinged to the table frame 70 (FIGURE 3) as denoted by reference character 72. Specifically, an intermediate shaft 74 is rotatably mounted on a pair of forwardly projecting table frame extensions 76. The extensions 76 are rounded at their forward ends to accommodate the arcuate front end 78 (FIGURE 2) forming a belt deflector portion of belt slide 114. The hinged table portion 68 is secured to the shaft 74 for angular displacement therewith by means of its rearwardly extending arms 82 with rigidly secured collars 84 thereon which are keyed or otherwise secured to the respective ends of the shaft 74.

The hinged table portion 68 can be raised to the chain outline position 86 to accommodate difiering pass elevations, or it can be dropped to its inactive position as denoted by chain outline 88. vIn either case the table portion 68 is displaced angularly by operating lever 90 rigidly joined at one end thereof to one of the collars 84 (FIGURE 3) and pivotally connected at its other end, reference character 92, to the connecting rod 94 of the piston and cylinder arrangement 64. When the hinged table portion 68 is displaced downwardly from its horizontal position as illustrated, the conveyor belt 62 glides over more or less of the arcuate deflector portion 78, depending upon the amount of downward displacement. At the lowermost position 88 of the hinged table portion 68, a limit switch 96 is engaged which controls suitable circuitry (not shown) to deenergize cylinder 64.

In this example the conveyor belt 62 is moved by driving one of the tensioning rolls, for example roll 60, which is driven, in this case, by drive chain 98, motor 100, and sprockets 102 and 104 coupled respectively to the motor and roll 60. The roll 60 engages the belt 62, when driven by the aforesaid drive chain, to impart continuous movement of the belt 62 about the belt rolls 54 60.

The rearward end of the table 48 has secured thereto a pivotally mounted table extension 106 which engages the strip as it emerges from the preceding mill stand to guide the head end of the strip onto the table 48 proper, where it engages the moving conveyor belt 62. The pivotal movement of the table extension 106 is controlled by piston and cylinder 108-. At the upper limit of movement, denoted by chain outline 110, limit switch 112 deenergizes cylinder 108.

Because it is undesirable to urge the strip from behind as stated above, means are associated with my apparatus and particularly with the belt table 48 for causing a slight pull to be exerted on the head end of the strip at this point. The pull which is thus exerted is sufficient to prevent the strip from cobbling or buckling as it is passed to the succeeding stand by the work rolls 24 of the preceding stand. The exerted pull also aids in maintaining the strip head at its proper location relative to the center line of the rolling mill.

In accordance with my invention, one arrangement for thus exerting a pull on the strip head, includes impregnating the conveyor belt 62 with a desirably pulverulent magnetic material, when the strip being reduced in the rolling mill is a magnetic material, as is usually the case. The provision of a magnetic belt in this fashion increases the frictional engagement of the strip therewith and with it the pull which is exerted upon the leading edge of the strip and that portion of the strip immediately preceding it.

Alternately in a second arrangement for exerting a pull on the strip head, stationary permanent magnets 80 are provided as shown in FIGURE 2. These magnets draw the strip against the belt by attracting the strip to themselves.

The speed of chain drive 98104 is speed-matched with work rolls 24 of the preceding stand so that the head end of the strip is pulled by the conveyor belt 62 rather than being urged from behind by the work rolls. Of course, as the head end of the strip proceeds along the upper portion or straight-away section 114 of the conveyor, the pull exerted by the belt increases which counterbalances the increasing tendency of the strip to buckle or cobble or deviate between adjacent mill stands as the head end approaches the succeeding stand of the mill. As the leading edge of the strip reaches the forward belt roll 56 by means of the cylinder 64 and hinged table portion 68, the latter can be elevated, so that the leading edge passes through the adjacent X-ray gauge 30 and wringer rolls 14, 28 (FIGURE 1).

However, before the leading edge of the strip leaves the straight-away section 114 of the conveyor means pro vided in accordance with this form of my invention are actuated to steer the leading edge of the strip in order to permit any required lateral corrections in the path of strip movement to realign the strip properly with the center line of the mill.

In pursuance of the aims of ing means in this arrangement includes pivotally mounting the table stand 52 adjacent its rearward end upon the supporting platform 50 as denoted by reference character 116. A suitable thrust bearing, of known design and denoted generally at 118 is associated with the aforementioned pivot mounting 116. Adjacent the forward end of the table stand 52, a pair of wheel supported brackets 120 are secured to the underside of the stand 52 and are disposed so that their wheels 122 engage, for example, a track member 124 supported on the upperside of the platform 50. As better shown in FIGURE 5, the wheels 122 are disposed for lateral movement of the forward end of the table stand 52, when the latter is angularly displaced about its rear pivot mounting 116-118. The wheels 122 preferably are canted relative to one another so as to be concentric respectively with radii extending from pivot axis 126 of the pivot mounting 116-118.

The forward end of the table stand 52 can be moved laterally in either direction of the center line of the rollin-g mill by means of a drive or steering piston and cylinder arrangement 128, which is connected between eyebrackets 130 and 132 secured respectively to the upper and lower surfaces of the platform 50 and the stand 52. When properly actuated in pursuance of the aims of my invention, the steering cylinder 128 pivots the table stand 52 so that the forward end swings to the right or to the left of the mill center line as required to counter-balance any similar, but opposite deviation of the strip from its position of alignment with the mill center line.

As better shown in FIGURES 45, in accordance with another feature of the steering cylinder 128 my invention can be actuated automatically in response to such deviations, although it is not essential for the practice of the previously described feature of my invention to do so. Components of FIGURES 4 and 5 which are similar to those illustrated and described above in connection with FIGURES l-3 are identified with similar reference characters with primed accents.

One arrangement for automatically actuating the steering cylinder 128 includes means sensitive to each lateral edge location of the strip, which means when energized, as by respective displacements of the lateral strip edges from their proper locations, are arranged to manipulate a spool valve 136 (FIGURE 6) or the like to control the lateral movements of reciprocating double-acting piston 138 of the steering cylinder 128. In this example, the edge sensitive means includes photoelectric cells 140 and 142 and respectively cooperating light sources such as lamps 144 and 146 disposed at the lateral edges 148 and 150 of the strip. Each photocell and lamp assembly 140, 144 or 142, 146 is spacedly mounted at a suitable elevation, (FIGURE 4) to accommodate the anticipated variation of pass elevation of the rolling mill. Each photocell and lamp assembly is mounted upon an upstanding bracket 152, which in turn is threadedly mounted upon a drive screw 154. The drive screw 154 is rotatably mounted adjacent its ends on suitable supports 156 which in turn are secured to a transversely extending table 158 which is supported directly upon the stand 50' and independently of the conveyor belt table 48' by means of a pair of opposed brackets 160. Thus the strip edge sensing means remains aligned with the rolling mill center line during corrective, lateral movements of the forward end of table The brackets 152 my invention, such steerare oppositely threaded relative to one another so that rotation of the drive screw 154 in one direction moves the brackets 152 toward one another, and in the opposite direction separates the brackets 152 so that varying widths of the strip can be accommodated therebetween. The photocell and lamp brackets 152 are further arranged so that rotation of the drive screw causes the brackets 152 to move through equal distances toward or away from the mill center line. The drive screw 154 can be rotated either manually or preferably by remotely energizable driving means as an electric motor drive 162.

The lamps 144, 146 desirably are provided with collimating means to produce a slit or point source of light and the brackets 152 are so disposed by the drive screw 154 that the energizing light rays normally falling upon the photocells 140, 142 are blocked by the edges 148 and respectively of the strip at the separation of the brackets 152 for a given width of properly aligned strip. Thus, a very slight deviation of the leading edge of the strip in either lateral direction causes one of the photocells 140, 142 to be energized. For example, deviation of the strip to the right, (arrow 186) when facing the rolling mill entrance, (FIGURE 6) causes the left lateral edge 150 of the strip to be displaced from the path of light rays from lamp 146 so that the photocell 142 is energized. Conversely, movement of the strip to the left causes the right lateral edge 148 to be displaced (not shown) from the path of light rays and the attendant energization of photocell 140 by its lamp 144.

Referring now more specifically to [FIGURE 6 of the drawings, the signals thus produced by the photocells 140 and 142 are respectively applied to the inputs of a pair of suitable amplifiers 164 and 166 of known construction. For this purpose, the photocells 140 and 142 are connected to the amplifiers through conductors 168 and 170 respectively. The outputs of the amplifiers are connected through conductors 172 and 174 to a pair of spool valve actuating solenoids 176 and 178 respectively. The solenoids 176 and 178 are coupled to the spool valve stem or operating rod 1-80 such that the right edge solenoid 176 when energized moves the stem 180 to the left as denoted by arrow 182 in FIGURE 6, while the right edge solenoid 178 moves the spool valve stem 180 in the opposite direction, as denoted by arrow 184. Therefore, when the strip has deviated to the right as viewed in FIGURE 6 (arrow 186) the photocell 142 is energized and the resultant energization of the solenoid 178 moves the valve stem 180 and spool valve members 188 to the right as indicated by arrow 184, with the result that hydraulic fluid is applied to the right side of the piston 138 so that the steering piston and cylinder arrangement 128' moves the forward end of the table 48 to the left, as denoted by arrows 190, to realign the strip with the mill center line.

In furtherance of this purpose, hydraulic pump 192 is connected to the spool valve 136 through a suitable and known conduit arrangement with the pump discharge denoted by arrow 194. This counter-balancing movement to the left of the forward end of the table 48' is continued until the strip is again realigned with the center line of the mill, at which time the left edge solenoid 178 is de-energized.

In the same manner, deviations of the strip to the left, as viewed in FIGURE 6, are counter-balanced by equal and opposite movements of the pivotal table 48 by energization of the right edge solenoid 176 to displace the spool valve members 188 and piston 138 in their opposite directions, as denoted by arrows 184 and 186, respectively. It is contemplated that the aforementioned corrective movements of the forward end of the table 48' will be slight distance-wise so that the table 48 will remain at all times in substantial alignment with the mill center line, to maintain the strip in perfect alignment therewith.

To facilitate altering the course of the strip by pivoting the belt table 48 in the aforedescribed manner, means are provided in accord with another feature of my invention, for temporarily making the strip more flexible about a vertical axis adjacent the conveyor belt 62' so that the application of relatively small corrective or steering forces to the strip are required, as the table 48 is pivoted. One arrangement for thus increasing the flexibility of the strip includes means for temporarily distorting the normal path of the strip as by putting a loop 196 in the strip adjacent its exit from the work rolls of the preceding stand, as better shown in FIGURE 4. With this spatial arrangement, the head end of the strip and the portions thereof intermediate the head end and the loop 196, i.e., those portions of the strip which are thus rendered more readily flexible, are almost entirely bracketed within the supporting or straight-away section 114 of the belt 62. Accordingly, sidewise motion of this portion of the strip can be more readily attained by pivoting the belt table with the application of relatively small forces to the strip so that cambering or skewing the strip is avoided.

One arrangement for producing the loop 196 includes the use of a looper roll 198 rotatably mounted between a pair of spaced pivotally mounted operating arms 200 therefor. The looper arms 200 are raised and lowered together with the roll 198 by means of a motor and drive screw arrangement 202, which angularly displaces the looper arms 200 about their pivotally mounted centers 204.

To describe the operation of the looper mechanism, reference will now be made to FIGURES 4 and 7 of the drawings. As the head end of the strip passes through the work rolls 24 of the preceding mill stand, a strain gauge or load sensing cell 206 senses the strain in the aforesaid stand and transmits an electrical signal to timer switch mechanism 208 (FIGURE 7). The timer switch mechanism 208 incorporates a time delay equal to the predetermined time required for the strip head to travel from the work rolls 24 to the far end or forward end of the conveyor belt 62', as represented by the position of forward roll 56'. At the expiration of this time interval, the timer switch mechanism 208 energizes control circuit 210 which stops the belt drive motor 100' thereby stopping the conveyor belt 62'. At the same time, the looper arm motor 202 is energized to raise the pivoted arms 200 and the looper roll 198 to form the loop 196. The angular speed of the looper roll is matched relative to the speed of the emergent strip head to maintain a slight tension in the loop 196, as the later is being formed by the looper roll.

When the looper arms 200 have been pivoted through a predetermined angular displacement, a limit switch 212 is engaged thereby, which re-energizes the belt drive motor '100' restoring the conveyor belt 62 to its speedmatched relationship with the work rolls 24. At the same time, the limit switch 212 reverses the rotational direction of the looper motor drive 202 so that the looper roll is returned to its inactive position leaving the loop 196 unsupported in the moving strip. Upon return to the at-rest position of the looper roll 198, a second limit switch 214 is actuated which de-energizes the looper motor 202.

It is contemplated that each stand of my tandem strip mill can be similarly equipped with the pivoted belt table 48 or 48 with or without the looper mechanism 198- 200. With this arrangement, the head or leading edge of the strip will be successively fed into the work rolls 24 at a perfectly aligned position thereof relative to the center line of the mill. The mill stands are, therefore, threaded successively at a common threading speed and at the completion of threading of a particular stand, the emergent leading portion of the strip can be placed in looper tension control, if desired, when the head end of the strip reaches the forward end of a succeding belt table.

From the foregoing, it will be apparent that novel and efiicient forms of a rolling mill, together with means associated therewith for automatically threading and centering the strip within the mill are disclosed herein. While I have shown and described certain presently preferred embodiments of the invention, and have illustrated cer tain presently preferred methods of practicing the same, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

I claim:

1. In a strip rolling mill, the combination comprising a pair of work roll stands, a pair of spaced conveyor belt rolls mounted adjacent the strip emergent side of one of said stands, a conveyor belt passing around said rolls, means for moving a strip engaging portion of said belt in the direction of strip movement to thread said strip through said rolling mill and to guide said strip to the entrance side of the other of said stands, said belt being moved at a speed sufiicient to exert a slight pull upon the leading portion of said strip as it is threaded through said mill owing to the frictional engagement of said belt with said strip to prevent cobbling or buckling of said strip, said belt rolls being mounted for rotation upon a pivotally mounted elongated support, said pivot mounting being disposed generally normal to the path of said strip and adjacent the rearward end of said support relative to strip movement so that the forward end of said support can be moved laterally relative to the center line of the mill to compensate deviations of said strip from its aligned position relative to said center line by moving the forward end of said support in a direction opposite to said deviations, and means for movably mounting the forward end of said support for said lateral movement thereof.

2. The combination according to claim 1 characterized in that said belt is provided with a magnetized material integral therewith for use with strip fabricated from magnetic material so that said frictional engagement of the strip and belt is increased.

3. The combination as claimed in claim 2 in which said belt is impregnated with magnetized material.

4. The combination as claimed in claim 2 wherein permanent magnets are fixed to said belt.

5. In a strip rolling mill, the combination comprising at least one mill stand having work rolls for compressingly engaging strip material when passed therebetween, conveyor belt means mounted adjacent the entrance side of said work rolls and adjacent and generally parallel to the path of strip movement through said mill, means for moving said conveyor belt when the leading end portion of said strip is supported thereon in order to guide the leading edge of said strip to said work rolls, said leading end portion frictionally engaging said conveyor belt so that a slight pull is exerted on said strip leading portion to prevent distortion thereof, means for mounting at least the forward end of said conveyor belt means for movement laterally of said rolling mill, and means for laterally moving said forward end to counter-balance opposite lateral deviations of said strip leading portion from said path.

6. In a strip rolling mill, the combination comprising at least one mill stand having work rolls for compressingly engaging strip material when passed therebetween, conveyor belt means mounted adjacent the entrance side of said work rolls and adjacent and generally parallel to the path of strip movement through said mill, means for moving said conveyor belt when the leading end portion of said strip is supported thereon in order to guide the leading edge of said strip to said work rolls, said leading end portion frictionally engaging said conveyor belt so that a slight pull is exerted on said strip leading portion to prevent distortion thereof, means for mounting at least the forward end of said conveyor belt means for movement laterally of said rolling mill, means for laterally moving said forward end to compensate opposite lateral deviations of said strip leading portion from said path, and means for imparting a transversely extending loop in said strip relative to said path when said strip leading portion is engaged with said conveyor means to facilitate lateral compensating movements thereof.

7. In a strip rolling mill, the combination comprising at least one mill stand having work rolls for compressingly engaging strip material when passed therebetween, conveyor belt means mounted adjacent the entrance side of said work rolls and adjacent and generally parallel to the path of strip movement, means for moving said conveyor belt when the leading end portion of said strip is supported thereon in order to guide the leading edge of said strip to said work rolls, said leading end portion frictionally engaging said conveyor belt so that a slight pull is exerted on said strip leading portion to prevent distortion thereof, means for mounting at least the forward end of said conveyor belt means for movement laterally of said rolling mill, means for laterally moving said forward end to compensate opposite deviations of said strip end portion from said path, means for imparting a transversely extending loop in said strip relative to said path when the leading edge portion thereof is engaged with said conveyor means to facilitate lateral compensating movements thereof, reversible driving means forming part of said lateral moving means, and means sensitive to the lateral edge displacement of said strip from said path for energizing said driving means to move said conveyor means forward end in a direction opposite to that of said edge displacement.

8. In a strip rolling mill, the combination comprising at least one mill stand having work rolls for compressingly engaging strip material when passed therebetween, conveyor belt means mounted adjacent the entrance side of said work rolls and adjacent and generally parallel to the path of strip movement, means for moving said conveyor belt when the leading end portion of said strip is supported thereon in order to guide the leading edge of said strip to said work rolls, said leading end portion frictionally engaging said conveyor belt so that a slight pull is exerted on said strip leading portion to prevent distortion thereof, means for mounting at least the forward end of said conveyor belt means for movement laterally of said rolling mill, means for laterally moving said forward end to counter-balance opposite deviations of said strip leading edge, reversible driving means forming part of said lateral moving means, and means sensitive to the lateral edge displacement of said strip from said path for energizing said driving means to move said conveyor means forward end in a direction opposite to that of said edge displacement.

9. In a strip rolling mill, the combination comprising at least one mill stand including work rolls, an elongated conveyor belt structure mounted adjacent the strip entrance side of said mill stand and generally parallel to the path of strip movement through said mill, means for guiding the leading edge of said strip onto said conveyor belt, means for moving said conveyor belt through said structure in the direction of strip movement through said rolling mill, means for pivotally mounting the rearward end portion of said conveyor belt structure whereby at least the forward end portion of said belt may move laterally relative to said rolling mill, reversible driving mechanism engaging the forward end of said conveyor belt structure to move the latter laterally of said strip path to counter-balance opposite deviations of said strip from its path, a pivotally mounted looper arm structure supported adjacent the rearward end of said conveyor belt structure, a looper roll rotatably mounted on an end of said looper arm structure adjacent a juxtaposed surface at said strip, said looper roll extending transversely of said strip, driving means for angularly displacing said looper arm structure in a direction to engage said looper roll with said strip surface to form a transversely extending loop in said strip.

10. The combination according to claim 9 characterized in that said reversible driving mechanism is actuated in one direction thereof by circuit means sensitive to the displacement of one lateral edge of said strip in a predetermined direction from said path, and in the other direction thereof by means sensitive to the displacement of the other lateral edge of said strip in the opposite of said predetermined direction from said path.

11. The combination according to claim 10 characterized in that circuit means are provided for energizing said looper arm drive means when the leading edge of said strip reaches a predetermined location along the length of the engaging portion of said conveyor belt.

12. In a strip rolling mill, the combination comprising a pair of work roll stands, a conveyor table including a hingedly secured forward end portion and positioned between said stands adjacent the strip emergent side of one of said stands, a pair of spaced belt rolls spacedly mounted on said table and said table portion respectively, a conveyor belt passing around said rolls, means for moving a strip engaging portion of said belt in the direction of strip movement to thread said strip through said roll ing mill and to guide said strip to the entrance side of the other of said stands, said belt being moved at a speed sufficient to exert a slight pull upon the leading portion of said strip as it is threaded through said mill owing to the frictional engagement of said belt with said strip to prevent cobbling or buckling of said strip, means for hingedly moving said table portion including the belt roll mounted thereon to raise and lower the adjacent conveyor belt portion to accommodate differing pass heights of said strip, said table being pivotally mounted for lateral angular displacement relative to said strip movement, and means for pivoting said table to correct opposite lateral deviations of said strip.

13. In a method for threading a strip rolling mill, the steps comprising initially conducting the leading edge of a strip in the path and direction of strip movement through said rolling mill, applying force to said strip in a direction to advance and guide said leading edge to the work rolls of a succeeding mill stand, applying said force at a rate suflicient to exert a pull on said leading edge and adjacent portions of said strip by frictional engagement therewith, laterally displacing the application of said force relative to said strip path in a direction to counter-balance opposite deviational movements of said strip from said path, and looping said strip transversely of said path at a position immediately preceding the application of said force to facilitate lateral corrective movements of said strip and of said force.

References Cited UNITED STATES PATENTS 739,493 9/ 1903 Horgeoves 72222 2,062,297 12/ 1936 Delany 72--14 2,192,409 3/ 1940 McBain 72-250 2,325,418 7/1943 Meyers 7214 2,331,246 10/ 1943 Stoltz 72-227 2,842,361 7/1958 Miller 226-21 3,040,944 6/ 1962 Andersen 22621 3,118,314 l/l964 Schuster 22622 3,322,963 5/1967 Pages 226-21 3,344,645 10/ 1967 Buccicone 72-2Sl FOREIGN PATENTS 725,594 9/ 1942 Germany. 547,060 10/ 1957 Canada.

CHARLES W. LANHAM, Primary Examiner.

A. RUDERMAN, Assistant Examiner.

U.S. Cl. X.R. 

